Rotary pump



P 0, 1955 F. M. KIRKPATRICK ROTARY PUMP Filed Dec. 31, 1952 UnitedStates Patent Ofifice 2,718,351 Patented Sept. 20, 1955 ROTARY PUMPFloyd M. Kirkpatrick, Erie, Pa., assignor to General Electric Company, acorporation of New York Application December 31, 1952, Serial No.328,961

4 Claims. (Cl. 230-137) My invention relates to pumps and moreparticularly to pumps of the rotary type.

It is an object of my invention to provide an improved rotary pumphaving an increased eificiency.

It is a more specific object of my invention to provide an improved ballpump of the type disclosed in my earlier Patent 2,611,534 includingprovision for minimizing leakage from the high pressure side to theintake.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In carrying out the objects of my invention the basic pump structuredisclosed in my earlier Patent 2,611,534 is employed. In order to avoidleakage from the high pressure side to the intake during the crossoverof the piston segments a slide moving transversely in the inlet recessis employed for blocking the intake passage during this portion of theoperating cycle.

For a better understanding of my invention reference may be had to theaccompanying drawing in which:

Fig. 1 is a view, partly broken away, of a refrigerating unit includinga compressor embodying my invention.

Fig. 2 is an enlarged plan view, partly broken away, of the compressorshown in Fig. 1.

Fig. 3 is a View of the rotor of the compressor, showing the pistonsegments in a different position than in Fig. 2.

Fig. 4 is a view similar to Fig. 3 showing the piston segments in stillanother position.

Fig. 5 is an elevation view, partly in section, of a portion of thecompressor showing the piston segments in the same position as in Fig.4.

In the following description, the pump is described in connection withits application as a compressor in a refrigerating apparatus but it willbe apparent that it may be utilized in many other applications wherepumping of fluid is required. Referring now to Fig. 1, there is shown ahermetically sealed case 1 within which is mounted a compressor 2. Thecompressor is positioned within the housing by rings 3 and 4 which fitgrooves in the case 1 and engage opposite faces of the compressor 2. Thecompressor is driven in any suitable manner as by an electric motor (notshown) incorporated within the case 1 and connected to the compressorthrough a drive shaft 5. Compressed refrigerant is discharged from thecompressor through conduits 6 and 7 into a common conduit 8 from whichit is circulated through the refrigerating system (not shown). Vaporizedrefrigerant is returned from the refrigerating system through a conduit9 which discharges the refrigerant into the interior of the case 1.Vaporized refrigerant within the case 1 is taken into the compressorthrough intake conduits 10 and 11, the open ends of which are positionedabove the level 12 of any liquid refrigerant or oil within the case 1.

As shown in more detail in Fig. 2 a compressor is driven through theshaft 5 which is supported within a bearing 13." Compressor includes ahousing 14 which is composed of two complementary parts 15 and 16. The

inner surface of each of the housing parts 15 and 16 is curved so thatwhen the two parts are assembled a spherical surface, forming aspherical chamber, is provided within the interior of the housing. Inthe form shown the housing parts are of such width that the ends of thesphere formed by the inner surfaces thereof are truncated. However, ifdesired, the housing could be enlarged and the inner surfaces of theparts 15 and 16 continued to provide a substantially complete sphere.The housing parts 15 and 16 are held in sealing engagement by devicessuch as screws 19 which pass through the upper housing part 15 and arearranged in threaded engagement with the lower housing part 16.

A rotor 17 is provided within the housing, the rotor being driven by theshaft 5. The outer surface of this rotor is curved to provide agenerally spherical surface having the same radius of curvature as theinner surface of the housing so as to rotate smoothly in engagementtherewith. In the form shown, the rotor also is truncated, providingflat faces 18 and 18'. An arcuate ring 20 which fits within a groove 21in the housing and engages the face 18 of the rotor may be employed toassist in resisting oscillation of the axis of rotation of the rotor,although reliance for this purpose may be placed entirely on the bearing13.

The rotor is provided with two circumferential grooves 22 and 23. Thesegrooves intersect each other at diametrically opposite points of therotor, one such intersection being indicated at 24. These grooves areinclined at equal angles with respect to a plane perpendicular to theaxis of rotation of the rotor and extending through the two points ofintersection of the grooves 22 and 23. In order to effect pumping offluid a piston segment 25 is positioned within the groove 22 and asimilar piston segment 26 is positioned within the groove 23. The outerspherical surfaces 27 and 28 of the piston segments 25 and 26respectively are in line with the spherical surface of the rotor 17 andhence are in engagement with the spherical surface provided by theinterior of the housing 14. Each of the piston segments is in the formof a semi-circular or half-annular section extending on a great circleof the rotor 17 substantially half the circumference thereof.

To effect pumping of fluid by the compressor, it is necessary torestrain the piston segments 25 and 26 against rotation with the rotorwhile permitting lateral oscillation of the segments during suchrotation of the rotor. This is accomplished by providing a pin orprojection on each of the piston segments pivotally engaging a slide orblock which is slidably positioned within a transverse slot or recess inthe housing 14. In the drawing one such slide or block 29 is shownpivotally connected by a pin 30 to the piston segment 26. It will beapparent, however, that exactly the same construction is employed at thediametrically opposite point for pivotal connection with and restraintof the other piston segment 27. Since my invention can be fullyunderstood, in view of the complete disclosure in my earlier Patent2,611,5 34, by a description of one such slide, illustration anddescription of a corresponding oppositely mounted slide has beenomitted. The slide 29 is slidably positioned for transverse movement, i.e., movement generally transverse of the piston segments, within anelongated transverse recess 31 formed in the housing adjacent the rotor17. The slide 29 is substantially the same Width as the width of therecess 31 and is substantially the same thickness as the depth of therecess 31. v

In the following description, the recess 31 is referred to as the intakerecess, one intake conduit 11 being connected to this recess generallycentrally of the length of the recess and providing an intake port, asindicated at 32. A second elongated transverse recess 33 is provided inthe housing 14, this recess being spaced from but adjacent to the recess31. The elongated transverse recess 33 will be referred to as thedischarge recess, this recess being connected to the discharge conduit6. It will be noted that the recesses 31 and 33 are circumferential-1yspaced on opposite sides of the cross over point of the pistonsegmen-ts. The crossover point as used in this specification indicatesthe point of intersection of the grooves 22 and 23 when the rotor is ina position that the ends of the piston segments are disposed in theregion of the intersection, as shown in Fig. 2. Another cross-overpoint, of course, occurs diametrically opposite from the one shown inFig. 2. Although not shown, it will be realized that correspondingintake and discharge recesses are provided at diametrically oppositepositions, also adjacent to each other and spaced on opposite sidescircumferentially of the other crossover point of the piston segments.

The pumping is accomplished in the structure herein disclosed in thesame manner as in the basic pump structure shown in my earlier Patent2,611,534. Thus, the rotor 17 moves, e. g., in the direction indicatedby the arrow, and the piston segments 25 and 26 are restrained fromcircumferential or rotating movement but are allowed to oscillatebetween the various successive positions, as shown, for example in Figs.2, 3 and 4. The position of the piston segments illustrated in Fig. 3shows the segments after a 180 rotation of the rotor from the positionshown in Fig. 2. Figs. 4 and 5 show the elements after an additional 90rotation of the rotor. For convenience in description and for ciaritythe intake recess 31 and the discharge recess 33 have been superimposedin dotted lines on the rotor in Figs. 3 and 4.

As described in detail in my aforementioned patent, the rotation of therotor and its grooves 22 and 23 and the oscillation of the pistonsegments 25 and 26 results in a pumping of the refrigerant from theintake conduit and intake recess to the discharge recess and dischargeconduit. A reference to Fig. 4 illustrates this operation. As there isseen, one face 34 of piston segment 26 blocks one end of thecircumferential groove 23. As the rotor revolves in the directionindicated, the size of the groove between the face 34 of the pistonsegment 26 and the end 35 of the piston segment 25 increases causingvaporized refrigerant to be drawn into this space from the intakeconduit 6 through intake port 32, which is superimposed in dotted linesin Figs. 3 and 4. At the same time, one end of the circumferentialgroove 22 is blocked by a face 36 of the piston segment 25. As the rotorrotates in the direction indicated by the arrow, the size of thecircumferential groove 22 between the face 36 of the piston segment 25and the end 37 of the piston segment 26 progressively decreases so thatvaporized refrigerant taken into this space in the previous half cycleof operation is compressed and pumped out through the discharge recess33 which is in communication with the groove 22. This compressedrefrigerant also passes through a discharge port 33, superimposed indotted lines in Figs. 3 and 4, to the discharge conduit 11. Theoperation of this aspect of my pump is described in great detail in myaforementioned Patent 2,611,534, and reference may be had to that patentfor further description, if felt necessary, of the details of the basicpump and the pumping operation. No further description of this operationis felt necessary here since the specific invention here disclosed hasto do with a particular improvement of this basic pump.

in Figs. 2 and 3 the piston segments are shown at what may be referredto as a crossover point, that is a point where the ends of the pistonsegments are disposed in the region of the intersection 24 of thecircumferential grooves 22 and 23. In Fig. 2 the piston segments areillustrated at one crossover point and in Fig. 3 at a second crossoverpoint occurring after a 180 rotation of the rotor 17. It will be seenthat there is no communication between the Cir intake recess anddischarge recess when the rotor is in the position shown, for example,in Fig. 4 since, as mentioned previously the spherical surface of therotor fits closely adjacent the spherical surface of the housing 14, andsince the ends 35 and 37 of the piston segments extend somewhat beyondthe corresponding recesses 33 and 31, all as set forth in my earlierPatent 2,611,534. However, there is communication between the twocircumferential grooves 22 and 23 during the short period when thepiston segments are at the crosover point. In the form of inventionshown in my aforementioned patent, a communication between the highpressure side and the intake conduit was possible during this relativelyshort period of rotation of the rotor and hence some reduction inefficiency resulted because of this leakage of compressed refrigerantinto the intake port and intake conduit. The invention in the presentapplication has specifically to do with positively blocking any flow ofrefrigerant from the high pressure side into the intake conduit duringthis portion of the operating cycle of the compressor when the pistonsegments are at the crossover point. This is accomplished by the slide29, its position within the corresponding intake recess 31, and itsrelationship to the intake port 32. The width of the slide 29 issubstantially the same as the width of the corresponding recess 31 sothat the slide moves smoothly along the recess during its oscillatingmovement. More pertinent, however, the thickness of the slide 29 issubstantially the same as the depth of the recess 31 so that the uppersurface 39 of the slide, as viewed in Fig. 5, rides closely adjacent thesurface 40 of the recess 31. It can be seen, therefore, that the slide29 is positioned so as to seal the intake port 32 when the slide 29extends thereacross.

In the position of the parts shown in Figs. 4 and 5, the slide 29 isclear of the intake port 32 so that it has no effect on the flow ofrefrigerant inwardly through the intake conduit 6 into the inlet recess31 and then into the communicating groove in the rotor 17. When therotor is in the position shown in Fig. 2 or Fig. 3, however, that iswhen the piston segments are at the crossover point or stated otherwisein the region of the intersection of the grooves 22 and 23, the slide 29occupies a position completely blocking the intake port 32. This isillustrated by showing the port 32 superimposed in dotted lines and canbe further visualized by the realization that at the crossover point theslide shown in Fig. 5 would be disposed substantially centrally of thelength of the elongated transverse intake recess 31. Since, as statedpreviously, the surface 39 of the slide rides closely adjacent to thesurface 40 of the recess, the slide in this central position blocks theintake port 32. Hence, under these circumstances, flow of compressedrefrigerant from the high pressure side through the communicatingcircumferential grooves 22 and 23 and into the intake conduit isblocked. This blockage of such flow increases the efficiency of thepump, since the flow of refrigerant in this manner represents a loss inthe operation of the pump.

The slide 29 is elongated and is made of sufficient length so thatduring the period of rotation when the piston segments are in the regionof the crossover point and hence when such flow of refrigerant from thehigh pressure side to the intake conduit would be possible, one end orthe other of the slide 29 completely blocks the intake port 32. Thus inthe crossover position shown in Fig. 2, the right-hand portion of theslide 22 insures this blocking of the intake port and in the positionshown in Fig. 3, the left-hand end of the slide 29 effects this lockingof the intake port. A check valve may be employed in the dischargeconduit 8 or, alternatively, as suggested in my Patent 2,611,534, acheck valve may be used in each of the discharge conduits 6 and 7,preferably close to the discharge ports to further assist in minimizingflow of refrigerant from the high pressure side to the intake.

The invention has been described and illustrated by reference to asingle intake and discharge recess and a single slide 29, but it will berealized, as pointed out above, that the identical structure is providedat the diametrically opposite side of the compressor. Duplicateillustration of this structure is not felt to be necessary for anunderstanding of my invention, particularly since this duplicateillustration is fully given in my aforementioned Patent 2,611,534.

While I have shown and described a specific embodiment of my invention,I do not desire my invention to be limited to the particularconstruction shown and described, and I intend by the appended claims tocover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A pump comprising a housing having a spherical chamber therein, arotor within said chamber, said rotor having a spherical surfacearranged to contact the surface of said chamber, said rotor having 'apair of circumferential grooves formed in said spherical surfacethereof, said grooves intersecting each other at two diametricallyopposite points, a semicircular piston segment positioned in each ofsaid grooves, two diametrically opposite elongated intake recesseswithin said housing adjacent said spherical surface of said rotor, twodiametrically opposite elongated discharge recesses within said housingadjacent said spherical surface of said rotor, each of said dischargerecesses being positioned adjacent one of said inlet recesses, all ofsaid recesses extending transversely with respect to said grooves, oneof said intake recesses and one of said discharge recesses communicatingwith each of said grooves, each of said discharge recesses beingcircumferentially spaced from the adjacent one of said intake recesses,adjacent intake and discharge recesses being disposed on opposite sidesof a plane extending between the ends of said segments and along theaxis of said rotor, an elongated slide pivotally connected to one ofsaid piston segments and slidably received within one of said intakerecesses for maintaining said one of said piston segments againstrotation with said rotor while permitting lateral oscillation of saidone of said piston segments, a second elongated slide pivotally engagingthe other of said piston segments and slidably received within the otherof said intake recesses for maintaining said other of said pistonsegments against rotation with said rotor while permitting lateraloscillation of said other of said piston segments, an intake port in thebottom of each of said intake recesses and centrally of the lengththereof, each of said ports providing for communication between thecorresponding one of said intake recesses and a corresponding inletconduit, each of said elongated slides being of substantially the samethickness as the depth of its corresponding recess whereby said slidesblock said intake ports when the ends of said piston segments are in theregion of the intersections of said grooves.

2. A pump comprising a housing having a spherical chamber therein, arotor Within said chamber, said rotor having a spherical surfacearranged to contact the surface of said chamber, said rotor having apair of circumferential grooves formed in said spherical surfacethereof, said grooves intersecting each other at two diametricallyopposite points, a semicircular piston segment positioned in each ofsaid grooves, two diametrically opposite elongated intake recesseswithin said housing adjacent said spherical surface of said rotor, twodiametrically opposite elongated discharge recesses within said housingadjacent said spherical surface of said rotor, each of said dischargerecesses being positioned adjacent one of said inlet recesses, all ofsaid recesses extending transversely with respect to said grooves, oneof said intake recesses and one of said discharge recesses communicatingwith each of said grooves, each of said discharge recesses beingcircumferentially spaced from the adjacent one of said intake recesses,adjacent intake and discharge recesses being disposed on opposite sidesof a plane extending between the ends of said segments and along theaxis of said rotor, an elongated slide pivotally connected to one ofsaid piston segments and slidably received within one of said intakerecesses for maintaining said one of said piston segments againstrotation with said rotor while permitting lateral oscillation of saidone of said piston segments, a second elongated slide pivotally engagingthe other of said piston segments and slidably received with in theother of said intake recesses for maintaining said other of said pistonsegments against rotation with said rotor while permitting lateraloscillation of said other of said piston segments, an intake port in thebottom of each of said intake recesses and centrally of the lengththereof, each of said ports providing for communication between thecorresponding one of said intake recesses and a corresponding inletconduit, each of said elongated slides being of substantially the samethickness as the depth of its corresponding recess and of such lengththat it overlaps its corresponding intake port when the ends of saidpiston segments are in the region of the intersections of said grooveswhereby said slides block said intake ports when the ends of said pistonsegments are in the region of the intersections of said grooves.

3. A housing having a spherical chamber therein, a rotor within saidchamber, said rotor having a spherical surface arranged to engage thesurface of said chamber, said rotor having a pair of circumferentialgrooves formed in said spherical surface thereof, said groovesintersecting each other at two diametrically opposite points, asemicircular piston segment positioned in each of said grooves, twodiametrically opposite elongated intake recesses Within said housingadjacent said spherical surface of said rotor, two diametricallyopposite elongated discharge recesses within said housing adjacent saidspherical surface of said rotor, each of said discharge recesses beingpositioned adjacent one of said inlet recesses, all of said recessesextending transversely with respect to said grooves, one of said intakerecesses and one of said discharge recesses communicating with each ofsaid grooves, each of said discharge recesses being circumferentiallyspaced from the adjacent one of said intake recesses, adjacent intakeand discharge recesses being disposed on opposite sides of a planeextending between the ends of said segments and along the axis of saidrotor, a pair of elongated slides each pivotally connected to one ofsaid piston segments and each slidably received within one of said intake recesses for maintaining said piston segments against rotation withsaid rotor while permitting lateral oscillation of said piston segments,an intake conduit communicating with each of said intake recesses, andmeans comprising said elongated slides for blocking said intake conduitwhen the ends of said piston segments are in the region of theintersections of said grooves, whereby said elongated slides preventleakage from the discharge of said pump to said intake conduit.

4. A pump comprising a housing having a spherical chamber therein, arotor within said chamber, said rotor having a spherical surfacearranged to engage the surface of said chamber, said rotor having a pairof circumferential grooves formed in said spherical surface thereof,said grooves intersecting each other at two diametrically oppositepoints, a semi-circular piston segment positioned in each of saidgrooves, two diametrically opposite elongated intake recesses withinsaid housing adjacent said spherical surface of said rotor, twodiametrically opposite elongated discharge recesses within said housingadjacent said spherical surface of said rotor, each of said dischargerecesses being positioned adjacent one of said inlet recesses, all ofsaid recesses extending transversely with respect to said grooves, oneof said intake recesses and one of said discharge recesses communicatingwith each of said grooves, each of said discharge recesses beingcircumferentially spaced from the adjacent one of said intake recesses,adjacent intake and discharge recesses being disposed on opposite sidesof a plane extending between the ends of said segments and along theaxis of said rotor, a pair of elongated slides each pivotally connectedto a different one of said piston segments and slidably received withina diflerent one of said intake recesses for maintaining said pistonsegments against rotation with said rotor while permitting lateraloscillation of said piston segments, an intake conduit communicatingwith each i of said intake recesses centrally of the length thereof,said elongated sIides being of such length that they block said 10intake conduits. when the ends of said piston segments are in the regionof the intersections of said grooves and afiord communication of saidintake conduits with said intake recesses during the remainder of eachrevolution of said rotor.

References Cited in the file of this patent UNITED STATES PATENTS2,611,534 Kirkpatrick Sept. 23, 1952

